A method for positioning and printing of synchronous or asynchronous input multi-matching towel blank

Abstract

The application discloses a positioning printing method for synchronous or asynchronous input of multiple-knitted-cloth towel blanks, which comprises the following steps: taking real-time photos of multiple-knitted-cloth towel blanks on a conveying belt, calibrating and enhancing the images, and then sequentially splicing the images to a photo buffer area to form a global photo of the conveying belt; detecting the positions of each towel block in the global photo; deforming a printing template pattern according to the detection result, and filling the printing template pattern into a corresponding position of a 'to-be-printed buffer area'; when the cloth is conveyed to below a nozzle, printing the pattern in the to-be-printed buffer area to realize accurate positioning printing. The application has the following advantages: multiple-knitted-cloth towel blanks can be simultaneously printed, the width of the conveying belt can be effectively utilized, printing errors caused by wrinkles or weft skew problems of single-knitted-cloth towel blanks are avoided, positioning printing problems of two or more parallel input towel blanks are solved, no work station is needed to control the synchronization of the cloth at the entrance of the conveying belt, manual work is saved, and accurate simultaneous printing of the cloth with little difference in specifications is allowed.

Description

A method for positioning and printing multiple rolls of unfinished towel fabric using synchronous or asynchronous input. Technical Field

[0001] This invention relates to the field of towel positioning printing technology, and in particular to a positioning printing method for synchronously or asynchronously inputting multiple continuous towel fabrics. Background Technology

[0002] Flatbed printing requires pre-color separation and plate making. During printing, rolls of fabric can be printed continuously, requiring strict control of weft skew. The dimensions of individual towels may have slight errors, increasing the difficulty of precise printing. Weft skew is more difficult to control for wider multi-piece towels. When printing multiple rolls of narrow fabric side-by-side on a flatbed printing machine, synchronization issues can easily arise. Digital printing printers can print a much richer range of colors than flatbed printing, and towels are increasingly using digital printers to print patterns. In conventional printing, single-piece towel fabric is fed onto a conveyor belt, and the pattern is printed directly in series, making it impossible to align the pattern with each towel. While horizontal single-piece multi-piece towel printing can effectively utilize the conveyor belt width, towels consist of a rectangular core with a napped center and a smooth edge, making them more prone to weft skew or wrinkling than regular fabrics, especially with wider widths. After continuous operation on the equipment, the weft skew may worsen, becoming increasingly difficult to control. Since narrow-width fabric is not prone to weft skew or wrinkles on the conveyor belt, in order to solve the problem of weft skew or wrinkles, it is possible to consider using multiple pieces of narrow-width continuous fabric to be fed into the conveyor belt in parallel for positioning printing. However, current positioning printers can only process single pieces of fabric.

[0003] The patents "A Digital Printing Method for Jacquard Fabric" (application number: CN201210212592.4) and "A Precise Registration Method for Long Line Images" (application number: CN202010588272.3), published in Chinese patent literature, can achieve precise registration of single-roll towel fabric. They can use the four corners of the towel as feature points or control points, searching for the four corners in a photograph. After finding the corners, they perform unidirectional registration on the left and right sides or seams, and unidirectional registration on the top and bottom seams. After registration, they use thin-plate spline interpolation to print the towel. The printing template is deformed and then filled into the corresponding position on the towel to achieve precise overprinting. However, when overprinting multiple parallel input towels, the towel fabrics are prone to misalignment and asynchronous operation. When there is significant misalignment between multiple towels, treating them as a whole for identification and processing can lead to several problems. Firstly, feature points are easily misjudged. Secondly, the pattern deformation can cause significant distortion between the left and right sides of the fabric, making the identification and printing process difficult and potentially resulting in misaligned prints. If manual intervention is used to correct misjudgments, it will reduce printing speed and production efficiency. Summary of the Invention

[0004] To address the problem of uncontrollable weft skew and wrinkles caused by the conveying of wide-width multi-piece continuous towel fabric in existing technologies, this invention provides a synchronous or asynchronous parallel input method for positioning and printing multi-piece continuous towel fabric. This method solves the problem of accurate registration of two or more pieces of parallel input continuous towel fabric, reduces the defect rate, makes full use of the conveyor belt width, increases output, saves labor, and supports accurate registration of single-piece continuous towel fabric.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for positioning and printing multi-roll continuous towel fabric with synchronous or asynchronous parallel input includes the following steps:

[0007] A method for positioning and printing multiple rolls of unfinished towel fabric with synchronous or asynchronous parallel input is disclosed. The method involves pre-fabricating towel templates and determining the positions of control points; setting up a global photo buffer and a print buffer; generating a global photo; detecting the towels; deforming the print template pattern according to the detection results and filling it into the print buffer at the corresponding positions of the towels; and then printing the print pattern filled in the print buffer according to the detection results of each roll of fabric. This method can simultaneously perform positioning and overprinting of multiple rolls of unfinished towel fabric with similar specifications, or perform positioning and overprinting of a single roll of unfinished towel. It solves the problem of accurate overprinting of two or more rolls of unfinished towel fabric with parallel input, reducing the defect rate and making full use of the conveyor belt width.

[0008] Preferably, the method first detects the number of parallel input towel fabrics in the photo buffer and the left and right edge positions of each fabric based on the grayscale difference between the towel fabric and the conveyor belt in the global image; then, based on the left and right edges of each towel fabric, the towel units in each fabric are independently detected and processed. This achieves the detection of towel units.

[0009] Preferably, the control points are located on the four sides of the towel template or the four sides of the towel core, and the locations of the control points are specified when inspecting the towels. If it is a horizontally multi-layered towel fabric, the towel template is pre-exposed for horizontal drying. Different towel inspection benchmarks can be selected.

[0010] As a preferred method, each towel unit in each strip of fabric is searched and filled using a method that searches the four sides of the towel:

[0011] S1. At the fabric scrap or the estimated top and bottom seams, i.e. above the towel, search for the left and right edges of the raw fabric.

[0012] S2. Search the top edge of the towel: Based on all the control points on the top edge of the towel template and the fabric edge position obtained in S1, set multiple vertical lines in the photo in the x direction proportionally, and then search for the intersection points of the vertical lines with the top and bottom seams of the towel; the line connecting the intersection points represents the top edge seam of the towel; the intersection points correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towel fabric, pre-expose a single towel template horizontally to obtain a multi-layer towel template, and then process it as a whole;

[0013] S3. Based on the height of the towel template and the results of S2, estimate the position of the bottom seam of the towel;

[0014] S4. Based on the results of S3, search for the estimated left and right edges of the raw fabric at the bottom seam of the towel.

[0015] S5. Search the bottom edge of the towel: Based on all the control points at the bottom edge of the towel template and the fabric edge position obtained in S4, set a vertical line in the x direction proportionally, and then search for the intersection of the vertical line with the top and bottom seams of the towel; the line connecting the intersection points represents the bottom edge seam of the towel; the intersection points correspond one-to-one with the control points at the bottom edge of the towel template.

[0016] S6. Search the left side of the towel: Based on all the control points on the left side of the towel template, set a horizontal line proportionally on the line connecting the left endpoints of the upper and lower seams of the towel obtained in S2 and S5. Then, search for the intersection of the horizontal line and the left edge of the towel fabric in the photo. The line connecting the intersection points represents the left side of the towel. The intersection points correspond one-to-one with the control points on the left side of the towel template. For horizontal multi-layer towels, the method for obtaining the actual position of the control points on the left and right seams between the towels is the same as the method for searching the bottom edge of the towel in S5, including setting a vertical line in the y direction and searching for the intersection points.

[0017] S7. Search the right side of the towel: Based on all the control points on the right side of the towel template, set a horizontal line on the line connecting the right ends of the upper and lower seams of the towel obtained in S2 and S5. Then search for the intersection of the horizontal line and the right edge of the towel fabric in the photo; the line connecting the intersection points represents the right side of the towel; the intersection points correspond one-to-one with the control points on the right side of the towel template.

[0018] S8. Using the thin-plate spline method, interpolate and deform the actual positions of the four sides of the towel obtained in S2, S5, S6, and S7 of the printing template pattern together with the corresponding control points in the template pattern, and then fill them into the positions of the towel in the print buffer area;

[0019] S9. If there is still a sufficiently long piece of raw fabric in the photo, proceed to S1 for further processing. This enables direct detection of the towel unit.

[0020] As a preferred method, each raw fabric towel unit is searched and filled using a method that searches the four sides of the core:

[0021] S1. Based on the fabric end or the estimated top of the core of the previous towel, search for the left and right edges of the greige fabric.

[0022] S2. Search the top edge of the core: Based on all the control points on the top edge of the towel template and the fabric edge position in S1, set a vertical line in the photo in the x direction proportionally, and then search for the intersection of the vertical line and the top edge of the core; the line connecting the points represents the top edge of the core; the intersection points correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the top edge of each core is processed from left to right; 2 layers are divided into two parts, and 3 layers are divided into 3 parts;

[0023] S3. Based on the core height in the template and the result of S2, estimate the position of the bottom edge of the core;

[0024] S4. Based on the results of S3, search for the estimated left and right edge positions of the greige fabric at the position below the core.

[0025] S5. Search for the bottom edge of the core: Based on all the control points of the bottom edge of the core in the towel template and the fabric edge position obtained in S4, set a vertical line in the x direction proportionally, and then search for the intersection of the vertical line and the bottom edge of the core; the line connecting the intersection points represents the bottom edge of the core; the intersection points correspond one-to-one with the control points of the bottom edge of the core in the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the bottom edge of the core of each core can be processed from left to right.

[0026] S6. Search for the left side of the core: Based on all the control points on the left side of the core in the towel template, set a horizontal line in the y direction proportionally on the line connecting the left endpoints of the upper and lower sides of the core obtained in S2 and S5. Then search for the intersection of the horizontal line and the left side of the towel fabric core in the photo; the line connecting the intersection points represents the left side of the core; the intersection points correspond one-to-one with the control points on the left side of the core of the towel template.

[0027] S7. Search for the right side of the core: Based on all the control points on the right side of the core in the towel template, set a horizontal line in the y direction proportionally on the line connecting the right endpoints of the upper and lower edges of the core obtained in S2 and S5. Then search for the intersection of the horizontal line and the right side of the towel fabric core in the photo; the line connecting the intersection points represents the right side of the core; the intersection points correspond one-to-one with the control points on the right side of the core in the towel template.

[0028] S8. Using the thin-plate spline method, interpolate and deform the printing template pattern by combining the points on the four sides of the core obtained in S2, S5, S6, and S7 with the corresponding control points in the template pattern, and then fill them into the printing buffer area at the positions corresponding to the towels mentioned above;

[0029] S9. If there is still a long enough piece of raw fabric in the photo, the lower edge of the core obtained in S5 can be used to estimate the upper edge position of the core of the next towel. Proceed to S1 for further processing. This achieves the identification of the core.

[0030] Preferably, after multiple rolls of unfinished towel fabric are processed independently, the patterns in the printed buffer are filled and moved along with the conveyor belt to the printer nozzle, where they are precisely aligned with the corresponding towel units, and inkjet printing begins. This achieves accurate printing.

[0031] Preferably, the buffer area includes a photo buffer area for caching a large image of the entire conveyor belt, and the buffer area increases synchronously with the forward movement of the conveyor belt. The two buffer areas are the same width as the conveyor belt and their length is longer than the distance between the photographing device and the printer printhead mount. The contents of the two buffer areas increase synchronously with the forward movement of the conveyor belt. This allows the content within the buffer area to be photographed and added as the conveyor belt moves forward, achieving buffering of the pattern to be printed.

[0032] Preferably, generating a global photograph involves taking real-time photos at the conveyor belt inlet, calibrating and enhancing the photos, and then stitching them sequentially to the end of the photo buffer area to form a global photograph that reflects the real-time status of the conveyor belt and the towel fabric. This facilitates obtaining complete photos of the towel.

[0033] Preferably, the towel detection also includes detecting the number and left / right position of the fabric on the conveyor belt; then, each piece of fabric is detected independently within its range, and the position of each towel in this piece of fabric is detected sequentially according to the order in which the towels appear. This achieves sequential detection of the towels in the fabric.

[0034] The present invention has the following advantages:

[0035] (1) Printing multiple pieces of fabric towels simultaneously can effectively utilize the width of the conveyor belt; (2) Avoid printing errors caused by wrinkles or weft skew problems that are easy to occur with single-piece wide multi-layer towels; (3) Solve the problem of positioning and printing two or more towels that are input in parallel; (4) At the entrance of the conveyor belt, there is no need to set up a station to control the synchronization of the fabric, saving manpower; (5) Allow fabrics with similar specifications to be printed accurately at the same time. Attached Figure Description

[0036] The accompanying drawings described below are merely exemplary. Those skilled in the art can derive other embodiments from the provided drawings without any creative effort.

[0037] Figure 1 is a schematic diagram of the steps of a method for positioning and printing multi-piece continuous towel fabric with synchronous or asynchronous parallel input according to the present invention.

[0038] Figure 2 is a schematic diagram of two-piece, two-strand towel fabric with asynchronous parallel input.

[0039] Figure 3 is a schematic diagram of the template and control points for searching towel seams. The left side shows a schematic diagram of towel deformation and control points; the right side shows the towel template and towel seam control points.

[0040] Figure 4 is a schematic diagram of the template and control points for searching the edge of the towel core. The left side shows the towel deformation and control points, and the right side shows the towel template and control points for the edge of the towel core.

[0041] In the diagram: 1-Conveyor belt; 2-Wool core; 3-Top and bottom seams; 4-Left and right seams; 5-Grey fabric; 6-Fabric end. Detailed Implementation

[0042] The following specific embodiments illustrate the implementation of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0043] A method for positioning and printing multiple rolls of unfinished towel fabric with synchronous or asynchronous parallel input includes the following steps: pre-fabricating towel templates and determining the positions of control points; setting up a global photo buffer area and a print buffer area; generating a global photo, detecting the towels within it, and then deforming the print template pattern according to the detection results and filling it into the print buffer area at the positions corresponding to the towels; and printing the print pattern filled in the print buffer area according to the detection results of each roll of unfinished fabric. This method can simultaneously perform positioning and overprinting of multiple rolls of unfinished towel fabric with similar specifications input synchronously or asynchronously, or it can perform positioning and overprinting of a single roll of unfinished towel. It solves the problem of accurate overprinting of two or more rolls of unfinished towels input in parallel, reducing the defect rate and making full use of the conveyor belt width.

[0044] In other embodiments, the number of parallel input towel fabrics in the photo buffer and the left and right edge positions of each fabric are first detected based on the grayscale difference between the towel fabric and conveyor belt 1 in the global photo. Then, based on the left and right edges of each towel fabric, the towel units in each fabric are detected and processed independently. This achieves the detection of towel units.

[0045] In other embodiments, the control points are located on the four sides of the towel template or the four sides of the core 2, and the location of the control points is specified when detecting the towel. If it is a horizontally multi-layered towel fabric, the towel template is pre-exposed for horizontal drying. Different towel detection benchmarks can be selected.

[0046] In other embodiments, a method of searching the four sides of the towel is used to search for and fill each towel unit in each strip of fabric:

[0047] S1. At the fabric end 6 or the estimated seam, search for the left and right edges of the greige fabric;

[0048] S2. Search the top edge of the towel: Based on all the control points on the top edge of the towel template and the fabric edge position obtained in S1, set multiple vertical lines in the photo in the x direction proportionally, and then search for the intersection of the vertical lines with the top and bottom seams of the towel 3; the line connecting the intersection points represents the top edge seam of the towel; the intersection points correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towel fabric, pre-expose a single towel template horizontally to obtain a multi-layer towel template, and then process it as a whole;

[0049] S3. Based on the height of the towel template and the results of S2, estimate the position of the bottom seam of the towel;

[0050] S4. Based on the results of S3, search for the left and right edges of the fabric here;

[0051] S5. Search the bottom edge of the towel: Based on all the control points at the bottom edge of the towel template and the fabric edge position obtained in S4, set a vertical line in the x direction proportionally, and then search for the intersection of the vertical line with the top and bottom seams of the towel; the line connecting the intersection points represents the bottom edge seam of the towel; the intersection points correspond one-to-one with the control points at the bottom edge of the towel template.

[0052] S6. Search the left side of the towel: Based on all the control points on the left side of the towel template, set a horizontal line proportionally on the line connecting the left endpoints of the upper and lower seams of the towel obtained in S2 and S5. Then, search for the intersection of the horizontal line and the left edge of the towel fabric in the photo. The line connecting the intersection points represents the left side of the towel. The intersection points correspond one-to-one with the control points on the left side of the towel template. For horizontal multi-layer towels, the actual positions of the control points on the left and right seams 4 between the towels are also found using the above method of finding the intersection points.

[0053] S7. Search the right side of the towel: Based on all the control points on the right side of the towel template, set a horizontal line on the line connecting the right ends of the upper and lower seams of the towel obtained in S2 and S5. Then search for the intersection of the horizontal line and the right edge of the towel fabric in the photo; the line connecting the intersection points represents the right side of the towel; the intersection points correspond one-to-one with the control points on the right side of the towel template.

[0054] S8. Using the thin-plate spline method, interpolate and deform the actual positions of the four sides of the towel obtained in S2, S5, S6, and S7 of the printing template pattern together with the corresponding control points in the template pattern, and then fill them into the positions of the towel in the print buffer area;

[0055] S9. If there is still a sufficiently long piece of raw fabric in the photo, proceed to S1 for further processing. This enables direct detection of the towel unit.

[0056] As a preferred method, each raw fabric towel unit is searched and filled using a method that searches the four sides of the core:

[0057] S1. Based on the fabric end or the estimated top of the core of the previous towel, search for the left and right edges of the greige fabric.

[0058] S2. Search the top edge of the core: Based on all control points on the top edge of the towel template and the fabric edge position in S1, set a vertical line in the photo proportionally in the x-direction, and then search for the intersection of the vertical line and the top edge of the core; the line connecting the points represents the top edge of the core; the intersection points correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the top edge of each core is processed from left to right; 2 layers are divided into two parts, and 3 layers are divided into 3 parts.

[0059] S3. Based on the core height in the template and the result of S2, estimate the position of the bottom edge of the core;

[0060] S4. Based on the results of S3, search for the left and right edges of the fabric here;

[0061] S5. Search for the bottom edge of the core: Based on all the control points of the bottom edge of the core in the towel template and the fabric edge position obtained in S4, set a vertical line in the x direction proportionally, and then search for the intersection of the vertical line and the bottom edge of the core; the line connecting the intersection points represents the bottom edge of the core; the intersection points correspond one-to-one with the control points of the bottom edge of the core in the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the bottom edge of the core of each core can be processed from left to right.

[0062] S6. Search for the left side of the core: Based on all the control points on the left side of the core in the towel template, set a horizontal line in the y direction proportionally on the line connecting the left endpoints of the upper and lower sides of the core obtained in S2 and S5. Then search for the intersection of the horizontal line and the left side of the towel fabric core in the photo; the line connecting the intersection points represents the left side of the core; the intersection points correspond one-to-one with the control points on the left side of the core of the towel template.

[0063] S7. Search for the right side of the core: Based on all the control points on the right side of the core in the towel template, set a horizontal line in the y direction proportionally on the line connecting the right endpoints of the upper and lower edges of the core obtained in S2 and S5. Then search for the intersection of the horizontal line and the right side of the towel fabric core in the photo; the line connecting the intersection points represents the right side of the core; the intersection points correspond one-to-one with the control points on the right side of the core in the towel template.

[0064] S8. Using the thin-plate spline method, interpolate and deform the printing template pattern by combining the points on the four sides of the core obtained in S2, S5, S6, and S7 with the corresponding control points in the template pattern, and then fill them into the printing buffer area at the positions corresponding to the towels mentioned above;

[0065] S9. If there is still a long enough piece of raw fabric in the photo, the lower edge of the core obtained in S5 can be used to estimate the upper edge position of the core of the next towel. Proceed to S1 for further processing. This achieves the identification of the core.

[0066] In other embodiments, after multiple rolls of unfinished towel fabric are processed independently, the patterns in the printed buffer are moved along with the conveyor belt to the printer nozzle, where they are precisely aligned with the corresponding towel units, and inkjet printing is then performed. This achieves accurate printing.

[0067] In other embodiments, the buffer area includes a photo buffer area for caching a large image of the entire conveyor belt and a buffer area for the image to be printed. The size of the buffer area increases synchronously with the movement of the conveyor belt. These two buffer areas are the same width as the conveyor belt and their length is longer than the distance between the photographing device and the printer nozzle mount. The contents of these two buffer areas increase synchronously with the movement of the conveyor belt, thus achieving buffering of the image to be printed.

[0068] In other embodiments, generating a global photograph includes taking a real-time photo at the conveyor belt inlet, calibrating and enhancing the photos, and then stitching them sequentially to the end of the photo buffer area to form a global photograph that reflects the real-time status of the conveyor belt and the towel fabric. This facilitates obtaining a complete photograph of the towel.

[0069] In other embodiments, towel detection further includes detecting the number and left / right position of the fabric on the conveyor belt; then, each piece of fabric is detected independently within its range, and the position of each towel in this piece of fabric is detected sequentially according to the order in which the towels appear. This achieves sequential detection of the towels in the fabric.

[0070] In other embodiments, as shown in FIG1, in a preferred embodiment, the present invention discloses a method for positioning and overprinting multiple rolls of continuous terry cloth with synchronous or asynchronous parallel input, comprising the following steps:

[0071] 1. Initialization: Pre-set the photo buffer and the image to be printed buffer. These two buffers are the same width and height as the conveyor belt, and logically, their contents can be considered to move synchronously with the conveyor belt. The photo buffer is used to cache a complete global photo of the conveyor belt and the towel fabric. The image to be printed buffer is used to store the image data to be printed. Pre-make the towel template and specify the position of the search control point. If it is a horizontally multi-layered towel fabric, the towel template needs to be horizontally connected in advance to match the actual fabric.

[0072] 2. Take real-time photos of multiple synchronous or asynchronous parallel inputs of continuous terry cloth; after calibration and image enhancement, the photos are stitched together sequentially at the end of the photo buffer area to form a large global photo that reflects the current status of the conveyor belt in real time;

[0073] 3. Detect each complete single towel in the photo buffer area, and deform the printing template pattern using a thin plate spline to make the deformed printing template pattern match the towel. Then fill the corresponding position of the towel in the print buffer area.

[0074] 3.1 Towel Recognition Method: Since there are multiple rolls of raw fabric in the global photo, it is difficult to process them uniformly. This invention simplifies the process by first detecting all the raw fabrics input in parallel in the photo and the left and right boundaries of each roll of raw fabric based on the grayscale difference between the towel and the conveyor belt in the photo.

[0075] 3.2 For each piece of towel fabric detected in 3.1, the detection and filling method for a single piece of towel fabric is applied within its left and right boundary range. Based on the core outline, the shape of each complete towel in the photograph is identified sequentially. Then, the towel printing template pattern is appropriately deformed to match the detected towel shape and filled into the corresponding position in the printing buffer area for overprinting. Since each piece of towel fabric is processed independently without interference, multiple consecutive pieces of towel fabric are allowed to advance asynchronously. This means that fabrics with similar towel unit specifications are allowed to be overprinted simultaneously. For example, if three pieces of fabric are overprinted simultaneously, the average height of the towel fabric on the left is 80 cm, the average height of the towel fabric in the middle is 81 cm, and the average height of the towel fabric on the right is 82 cm.

[0076] 3.3 Based on the special requirement that only the core needs to be accurately aligned during towel overprinting, search for towel units along the four sides of the core, as shown in Figure 4:

[0077] S1. Based on the fabric scrap or the estimated top edge of the core of the previous towel, search for the left and right edges of the greige fabric.

[0078] S2. Search the top edge of the core: Based on all the control points on the top edge of the towel template and the fabric edge position in S1, set some vertical lines in the photo in the x direction proportionally, and then search for the intersections of these vertical lines with the top edge of the core; the line connecting these points represents the top edge of the core; these intersections correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the top edge of each core is processed from left to right; 2 layers are divided into two parts, and 3 layers are divided into 3 parts;

[0079] S3. Based on the core height in the template and the result of S2, estimate the position of the bottom edge of the core;

[0080] S4. Based on the results of S3, search for the left and right edges of the greige fabric here;

[0081] S5. Search the bottom edge of the core: Based on all the control points of the bottom edge of the core in the towel template and the fabric edge position obtained in S4, set some vertical lines in the x direction proportionally, and then search for the intersection points of these vertical lines with the bottom edge of the core; the line connecting these intersection points represents the bottom edge of the core; these intersection points correspond one-to-one with the control points of the bottom edge of the core in the towel template; for horizontal multi-layer towels, the fabric edge range can be divided equally according to the number of layers, and then the bottom edge of each core is processed from left to right; 2 layers are divided into two parts, and 3 layers are divided into 3 parts;

[0082] S6. Search for the left side of the core: Based on all the control points on the left side of the core in the towel template, set some horizontal lines in the y direction proportionally on the line connecting the left endpoints of the upper and lower sides of the core obtained in S2 and S5. Then search for the intersection points of these horizontal lines with the left side of the towel fabric core in the photo; the line connecting these intersection points represents the left side of the core; these intersection points correspond one-to-one with the control points on the left side of the core of the towel template.

[0083] S7. Search the right side of the core: Based on all the control points on the right side of the core in the towel template, set some horizontal lines in the y direction proportionally on the line connecting the right endpoints of the upper and lower edges of the core obtained in S2 and S5. Then search the photo for the intersection points of these horizontal lines with the right side of the towel fabric core; the line connecting these intersection points represents the right side of the core; these intersection points correspond one-to-one with the right side control points of the core in the towel template.

[0084] S8. Using the thin-plate spline method, interpolate and deform the printing template pattern by combining the points on the four sides of the core obtained in S2, S5, S6, and S7 with the corresponding control points in the template pattern, and then fill them into the printing buffer area at the positions corresponding to the towels mentioned above;

[0085] S9. If there is still a long enough piece of raw fabric in the photo, the bottom edge of the core obtained in S5 can be used to estimate the top edge of the core of the next towel, and then proceed to S1 to continue processing.

[0086] After multiple rolls of unfinished towel fabric are processed independently, the patterns in the printed buffer are filled and moved along with the conveyor belt to the printer nozzle. They are then aligned with the corresponding towel units, and inkjet printing is performed to achieve precise registration.

[0087] In another embodiment, searching for towel units based on the towel seam, i.e., the four-sided contour of the towel unit, as shown in Figure 3, includes the following steps:

[0088] S1. At the fabric end or the estimated seam (also known as the cut line), search for the left and right edges of the greige fabric;

[0089] S2. Search the top edge of the towel: Based on all the control points on the top edge of the towel template and the fabric edge position obtained in S1, set some vertical lines in the photo in the x direction proportionally, and then search for the intersections of these vertical lines with the top and bottom seams of the towel; the line connecting these intersections represents the top edge seam of the towel; these intersections correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towel fabric, a single towel template can be horizontally connected and dried in advance to obtain a multi-layer towel template, and then processed as a whole;

[0090] S3. Based on the template height and the results of S2, estimate the position of the bottom seam of the towel;

[0091] S4. Based on the results of S3, search for the left and right edges of the greige fabric here;

[0092] S5. Search the bottom edge of the towel: Based on all the control points at the bottom edge of the towel template and the fabric edge position obtained in S4, set some vertical lines in the x direction proportionally, and then search for the intersections of these vertical lines with the top and bottom seams of the towel; the line connecting these intersections represents the bottom seam of the towel; these intersections correspond one-to-one with the control points at the bottom edge of the towel template.

[0093] S6. Search the left side of the towel: Based on all the control points on the left side of the towel template, set some horizontal lines proportionally on the line connecting the left endpoints of the upper and lower seams of the towel obtained in S2 and S5. Then search for the intersections of these horizontal lines with the left edge of the towel fabric in the photo; the line connecting these intersections represents the left side of the towel; these intersections correspond one-to-one with the control points on the left side of the towel template; for horizontal multi-layer towels, the actual positions of the control points on the left and right seams between the towels can also be found using a similar method of finding intersections.

[0094] S7. Search the right side of the towel: Based on all the control points on the right side of the towel template, set some horizontal lines on the line connecting the right ends of the upper and lower seams of the towel obtained in S2 and S5. Then search for the intersections of these horizontal lines with the right edge of the towel fabric in the photo; the line connecting these intersections represents the right side of the towel; these intersections correspond one-to-one with the control points on the right side of the towel template.

[0095] S8. Using the thin-plate spline method, interpolate and deform the actual positions of the four sides of the towel obtained from S2, S5, S6, and S7, together with the corresponding control points in the template pattern, and then fill them into the positions corresponding to the towel in the print buffer area;

[0096] S9. If there is still enough raw fabric in the photo, proceed to S1 to continue processing.

[0097] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for positioning and printing multiple rolls of continuous raw towel fabric using synchronous or asynchronous input, characterized in that: Pre-make a towel template and determine the location of control points; Set up a global photo buffer and a print buffer; first, based on the grayscale difference between the towel fabric and the conveyor belt in the global photo, detect how many pieces of input towel fabric are in the photo buffer, and the left and right edge positions of each piece of fabric; first determine how many pieces of towel are there, and then, based on the left and right ranges of each piece of towel fabric, independently detect and process the towel units in each piece of fabric. A global photo is generated, and the towels within it are detected. The printed template pattern is then deformed according to the detection results and filled into the corresponding positions of the towels in the print buffer area. The print pattern filled in the print buffer area according to the detection results of each piece of fabric is then printed. The buffer area includes a photo buffer area for the global photo of the conveyor belt, and the content in the buffer area increases synchronously with the movement of the conveyor belt. The detection of towels also includes detecting the number and left and right positions of the fabric on the conveyor belt. Then, each piece of fabric is detected independently within its range, and the positions of each towel in the fabric of this piece of fabric are detected in the order in which the towels appear.

2. The method for positioning and printing multiple bolts of continuous terry cloth using synchronous or asynchronous input as described in claim 1, characterized in that, The control points are located on the four sides of the towel template or the four sides of the towel core, and the location of the control points is specified when detecting the towel.

3. The method for positioning and printing multiple rolls of continuous terry cloth using synchronous or asynchronous input as described in claim 1, characterized in that, This includes searching and filling each towel unit in each fabric strip using a method that searches the four sides of the towel: S1. Search for the left and right edges of the fabric strip at the fabric edge or the estimated top and bottom seams; S2. Search the top edge of the towel: Based on all the control points on the top edge of the towel template and the edge positions obtained in S1, set multiple vertical lines in the photo proportionally in the x-direction, and then search for the intersections of the vertical lines with the top and bottom seams of the towel; the line connecting the intersections represents the top seam of the towel; the intersections correspond one-to-one with the control points on the top edge of the towel template; for horizontally multi-layered towel fabrics, pre-expose single towel templates horizontally to obtain multi-layered towel templates, and then process them as a whole; S3. Estimate the position of the bottom seam of the towel based on the height of the towel template and the results of S2; S4. Based on the results of S3, search for the estimated left and right edge positions of the fabric at the bottom seam of the towel; S5. Search the bottom edge of the towel: Based on all the control points on the bottom edge of the towel template and the edge positions obtained in S4, set a vertical line proportionally in the x-direction, and then search for the intersection of the vertical line with the top and bottom seams of the towel; the line connecting the intersection points represents the bottom seam of the towel; the intersection points correspond one-to-one with the control points on the bottom edge of the towel template; S6. Search the left side of the towel: Based on all the control points on the left side of the towel template, set a horizontal line proportionally on the line connecting the left endpoints of the top and bottom seams of the towel obtained in S2 and S5, and then search for the intersection of the horizontal line with the left edge of the towel fabric in the photo; the line connecting the intersection points represents the left side of the towel; the intersection points correspond one-to-one with the control points on the left side of the towel template; for horizontal multi-layer towels, the left edge of the towel... The method for obtaining the actual position of the control point on the right seam is the same as that for searching the bottom edge of the towel in S5; S7. Search the right side of the towel: Based on all the control points on the right side of the towel template, set a horizontal line on the line connecting the right ends of the upper and lower seams of the towel obtained in S2 and S5, and then search for the intersection of the horizontal line and the right edge of the towel fabric in the photo; the line connecting the intersection points represents the right side of the towel; the intersection points correspond one-to-one with the control points on the right side of the towel template; S8. Use the thin plate spline method to interpolate and deform the printing template pattern together with the actual positions of the four sides of the towel obtained in S2, S5, S6, and S7 and the corresponding control points in the template pattern, and then fill it into the position corresponding to the towel in the print buffer area; S9. If there is still a long enough piece of fabric in the photo, go to S1 to continue processing.

4. The method for positioning and printing multiple bolts of continuous terry cloth using synchronous or asynchronous input as described in claim 1, characterized in that, This includes searching and filling each fabric towel unit using a method that searches the four sides of the core: S1. Search the left and right edges of the fabric based on the estimated top edge of the core, either from the fabric end or from the bottom edge of the previous towel core. S2. Search for the top edge of the core: Based on all the control points on the top edge of the towel template and the fabric edge position in S1, set a vertical line in the photo in the x-direction proportionally, and then search for the intersection of the vertical line and the top edge of the core; the line connecting the points represents the top edge of the core; the intersection points correspond one-to-one with the control points on the top edge of the towel template; for horizontal multi-layer towels, divide the fabric edge range equally according to the number of layers, and then process the top edge of each core piece from left to right; S3. Based on the core height in the template and the results of S2, estimate the position of the bottom edge of the core; S4. Based on the results of S3, search for the left and right edges of the greige fabric at the bottom edge of the core. S5. Search for the bottom edge of the core: Based on all the control points of the bottom edge of the core in the towel template and the fabric edge position obtained in S4, set a vertical line in the x direction proportionally, and then search for the intersection of the vertical line and the bottom edge of the core. The line connecting the intersection points represents the bottom edge of the core; the intersection points correspond one-to-one with the control points on the bottom edge of the core of the towel template; for horizontal multi-layer towels, the fabric edge range is divided equally according to the number of layers, and then the bottom edge of each core is processed from left to right.

5. A method for positioning and printing multiple rolls of continuous terry cloth using synchronous or asynchronous input as described in any one of claims 1 to 4, characterized in that, After multiple rolls of unfinished towel fabric are processed independently, the patterns in the printed buffer are filled and moved along with the conveyor belt to the printer nozzle, where they are aligned with the corresponding towel units, and inkjet printing begins.

6. The method for positioning and printing multiple bolts of continuous terry cloth using synchronous or asynchronous input as described in claim 1, characterized in that, The process of generating a global photo involves taking real-time photos at the conveyor belt inlet, calibrating and enhancing the photos, and then stitching them sequentially to the end of the photo buffer area to form a global photo that reflects the real-time status of the conveyor belt and the towel fabric.

7. The method for positioning and printing multiple bolts of continuous terry cloth using synchronous or asynchronous input as described in claim 4, characterized in that, The method of searching the four sides of the core and filling each fabric towel unit also includes: S6. Searching the left side of the core: Based on all the control points on the left side of the core in the towel template, a horizontal line is set proportionally in the y-direction on the line connecting the left endpoints of the upper and lower sides of the core obtained in S2 and S5. Then, the intersection of the horizontal line and the left side of the fabric towel core is searched in the photo; the line connecting the intersection points represents the left side of the core; the intersection points correspond one-to-one with the control points on the left side of the core in the towel template; S7. Searching the right side of the core: Based on all the control points on the right side of the core in the towel template, a horizontal line is set proportionally in the y-direction on the line connecting the right endpoints of the upper and lower sides of the core obtained in S2 and S5. Set the horizontal lines proportionally, then search for the intersection of the horizontal lines and the right side of the towel fabric core in the photo; the line connecting the intersection points represents the right side of the core; the intersection points correspond one-to-one with the control points on the right side of the towel template core; S8. Use the thin plate spline method to interpolate and deform the print template pattern, using the points on the four sides of the core obtained in S2, S5, S6, and S7 together with the corresponding control points in the template pattern, and then fill them into the print buffer area corresponding to the positions of the towels mentioned above; S9. If there is still a sufficiently long piece of fabric in the photo, the lower edge of the core obtained in S5 is used to estimate the upper edge position of the core of the next towel, and then go to S1 to continue processing.

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